Samsung has already signaled it doesn't expect great results. The smartphone market leader said earlier this month that revenue will be essentially flat and analysts expect a slide of 8.5 percent in net profit.

But that's the company as a whole. Its mobile division reported a drop in profit in the July to September quarter after it cut the price of the Galaxy S6 and S6 Edge to help boost sales. And like Apple, it's predicted a slowdown in sales growth.

Samsung is locked in stiff competition with Apple on the high end and that's unlikely to let up.

It has been pushing low- to mid-range handsets in developing markets, but Apple's comments about worldwide demand are worrying.